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Light sees gender of the silkworm pupa

We all know about silk and its smooth and uniquely beautiful apparels but know very little all processes that help transform tiny butterfly’s eggs into silk-based products. One of several important processes for obtaining long and high quality raw silk and sustaining high quality breeders is silkworm gender identification. It is accomplished by asking well-trained officers to visually inspect at the abdomen segment of the silkworm pupae. Although this non-destructive approach is cost effective for several developing countries, it is very time consuming and affects the eye sight of the officer.

Rather than investigating vulnerable parameters of the silkworm such as its mass and shape or utilizing expensive equipment such as optical spectrometers and magnetic resonance imaging systems, a very simple optical means via penetration of light through the silkworm pupa is exploited (1-3). Below figure shows that the image contrast of an important organ of the female silkworm pupa is clearly observed under the penetration of red light. This simple approach is actually similar to a familiar activity where we illuminate light from a light emitting diode on one side of our fingertip and see light coming out from the other side.

In addition, analyzing the image via simple image processing operations such as image thresholding and blob filtering can assist in leveraging the accuracy in identifying the gender of the silkworm pupa to > 95%. To answer all practical issues from users, additional key components such as a rotating disk, solenoid valves, a stepping motor, and an electronic controlling unit are also integrated into our system called GS2 (see Figure below). Not only does it function to identify gender of the silkworm pupa but also separate the female and male silkworm pupae into different baskets at a speed of 20 silkworms per minute.

Currently, five GS2 systems are developed for and deployed at five Queen Sirikit Sericulture Centers (QSCs) in Thailand, thus providing efficient means for officers to accurately identify and separate the gender of silkworm pupae. User feedbacks have also been collected for future improvement.

An officer of QSC in Thailand is using the GS2 for identifying and separating gender of silkworm pupae. Credit: Sarun Sumriddetchkajorn.

Sarun Sumriddetchkajorn received his B.Eng. in electrical engineering with honors in 1994 from Khon Kaen University, Thailand. He earned his M.S. and Ph.D. in optical science and engineering in 1998 and 2000, respectively, from University of Central Florida. He is now Executive Director of Thailand’s National Electronics and Computer Technology Center (NECTEC), National Science and Technology Development Agency (NSTDA), Ministry of Science and Technology. His research interest is in the photonic area where he applies photonics to solve problems for industrial, medical, environmental, and education sectors.

He is a recipient of the 2005 ICO/ICTP Award from the International Commission for Optics (ICO) and the Abdus Salam International Centre for Theoretical Physics (ICTP). In 2002, he initiated the formation of the OSA, SPIE, and IEEE-LEOS Thailand Chapters. He is a Senior Member of IEEE and OSA as well as a Fellow of SPIE and an SPIE invited lecturer.

Chakkrit Kamtongdee received B.Eng., M.Eng., and Ph.D. in Electrical Engineering from Khon Kaen University in Thailand in 2008, 2009, and 2014, respectively. He is now a post-doctoral researcher of NECTECs’ Photonics Technology Laboratory. His research interests are related to applications of photonics in agriculture.